21256022811 has 32 divisors (see below), whose sum is σ = 30840049728. Its totient is φ = 12968017920.

The previous prime is 21256022803. The next prime is 21256022831. The reversal of 21256022811 is 11822065212.

It is not a de Polignac number, because 21256022811 - 2³ = 21256022803 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21256022831) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3924141 + ... + 3929553.

It is an arithmetic number, because the mean of its divisors is an integer number (963751554).

Almost surely, 2^21256022811 is an apocalyptic number.

21256022811 is a deficient number, since it is larger than the sum of its proper divisors (9584026917).

21256022811 is a wasteful number, since it uses less digits than its factorization.

21256022811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7551.

The product of its (nonzero) digits is 3840, while the sum is 30.

The spelling of 21256022811 in words is "twenty-one billion, two hundred fifty-six million, twenty-two thousand, eight hundred eleven".